WebViewJavascriptBridge

An iOS/OSX bridge for sending messages between Obj-C and JavaScript in UIWebViews/WebViews.

If you like WebViewJavascriptBridge you may also want to check out WebViewProxy.

In the Wild

WebViewJavascriptBridge is used by a range of companies and projects. This list is incomplete, but feel free to add your's and send a PR.

Setup & Examples (iOS & OSX)

Start with the Example Apps/ folder. Open either the iOS or OSX project and hit run to see it in action.

To use a WebViewJavascriptBridge in your own project:

Drag the WebViewJavascriptBridge folder into your project.

In the dialog that appears, uncheck "Copy items into destination group's folder" and select "Create groups for any folders"

Import the header file:

#import "WebViewJavascriptBridge.h"
Instantiate WebViewJavascriptBridge with a UIWebView (iOS) or WebView (OSX):

WebViewJavascriptBridge* bridge = [WebViewJavascriptBridge bridgeForWebView:webView handler:^(id data, WVJBResponseCallback responseCallback) { NSLog(@"Received message from javascript: %@", data); responseCallback(@"Right back atcha"); }];
Go ahead and send some messages from ObjC to javascript:

[bridge send:@"Well hello there"]; [bridge send:[NSDictionary dictionaryWithObject:@"Foo" forKey:@"Bar"]]; [bridge send:@"Give me a response, will you?" responseCallback:^(id responseData) { NSLog(@"ObjC got its response! %@", responseData); }];

Finally, set up the javascript side:

function connectWebViewJavascriptBridge(callback) { if (window.WebViewJavascriptBridge) { callback(WebViewJavascriptBridge) } else { document.addEventListener('WebViewJavascriptBridgeReady', function() { callback(WebViewJavascriptBridge) }, false) } }

connectWebViewJavascriptBridge(function(bridge) {

 /* Init your app here */

 bridge.init(function(message, responseCallback) {
 	alert('Received message: ' + message)   
 	if (responseCallback) {
 		responseCallback("Right back atcha")
 	}
 })
 bridge.send('Hello from the javascript')
 bridge.send('Please respond to this', function responseCallback(responseData) {
 	console.log("Javascript got its response", responseData)
 })

})

Contributors & Forks

Contributors: https://github.com/marcuswestin/WebViewJavascriptBridge/graphs/contributors

Forks: https://github.com/marcuswestin/WebViewJavascriptBridge/network/members

API Reference

ObjC API

`[WebViewJavascriptBridge bridgeForWebView:(UIWebView/WebView*)webview handler:(WVJBHandler)handler]`

`[WebViewJavascriptBridge bridgeForWebView:(UIWebView/WebView)webview webViewDelegate:(UIWebViewDelegate)webViewDelegate handler:(WVJBHandler)handler]`

Create a javascript bridge for the given web view.

The WVJBResponseCallback will not be nil if the javascript expects a response.

Optionally, pass in webViewDelegate:(UIWebViewDelegate*)webViewDelegate if you need to respond to the web view's lifecycle events.

Example:

[WebViewJavascriptBridge bridgeForWebView:webView handler:^(id data, WVJBResponseCallback responseCallback) {
	NSLog(@"Received message from javascript: %@", data);
	if (responseCallback) {
		responseCallback(@"Right back atcha");
	}
}]

[WebViewJavascriptBridge bridgeForWebView:webView webViewDelegate:self handler:^(id data, WVJBResponseCallback responseCallback) { /* ... */ }];

`[bridge send:(id)data]`

`[bridge send:(id)data responseCallback:(WVJBResponseCallback)responseCallback]`

Send a message to javascript. Optionally expect a response by giving a responseCallback block.

Example:

[bridge send:@"Hi"];
[bridge send:[NSDictionary dictionaryWithObject:@"Foo" forKey:@"Bar"]];
[bridge send:@"I expect a response!" responseCallback:^(id responseData) {
	NSLog(@"Got response! %@", responseData);
}];

`[bridge registerHandler:(NSString*)handlerName handler:(WVJBHandler)handler]`

Register a handler called handlerName. The javascript can then call this handler with WebViewJavascriptBridge.callHandler("handlerName").

Example:

[bridge registerHandler:@"getScreenHeight" handler:^(id data, WVJBResponseCallback responseCallback) {
	responseCallback([NSNumber numberWithInt:[UIScreen mainScreen].bounds.size.height]);
}];

`[bridge callHandler:(NSString*)handlerName data:(id)data]`

`[bridge callHandler:(NSString*)handlerName data:(id)data responseCallback:(WVJBResponseCallback)callback]`

Call the javascript handler called handlerName. Optionally expect a response by giving a responseCallback block.

Example:

[bridge callHandler:@"showAlert" data:@"Hi from ObjC to JS!"];
[bridge callHandler:@"getCurrentPageUrl" data:nil responseCallback:^(id responseData) {
	NSLog(@"Current UIWebView page URL is: %@", responseData);
}];

Custom bundle

WebViewJavascriptBridge requires WebViewJavascriptBridge.js.txt file that is injected into web view to create a bridge on JS side. Standard implementation uses mainBundle to search for this file. If you e.g. build a static library and you have that file placed somewhere else you can use this method to specify which bundle should be searched for WebViewJavascriptBridge.js.txt file:

`[WebViewJavascriptBridge bridgeForWebView:(UIWebView/WebView)webView webViewDelegate:(UIWebViewDelegate)webViewDelegate handler:(WVJBHandler)handler resourceBundle:(NSBundle*)bundle`

Example:

[WebViewJavascriptBridge bridgeForWebView:_webView
                          webViewDelegate:self
                                  handler:^(id data, WVJBResponseCallback responseCallback) {
                                      NSLog(@"Received message from javascript: %@", data);
                                  }
                           resourceBundle:[NSBundle bundleWithURL:[[NSBundle mainBundle] URLForResource:@"ResourcesBundle" withExtension:@"bundle"]]
];

Javascript API

`document.addEventListener('WebViewJavascriptBridgeReady', function onBridgeReady(event) { ... }, false)`

Always wait for the WebViewJavascriptBridgeReady DOM event.

Example:

document.addEventListener('WebViewJavascriptBridgeReady', function(event) {
	var bridge = event.bridge
	// Start using the bridge
}, false)

`bridge.init(function messageHandler(data, response) { ... })`

Initialize the bridge. This should be called inside of the 'WebViewJavascriptBridgeReady' event handler.

The messageHandler function will receive all messages sent from ObjC via [bridge send:(id)data] and [bridge send:(id)data responseCallback:(WVJBResponseCallback)responseCallback].

The response object will be defined if if ObjC sent the message with a WVJBResponseCallback block.

Example:

bridge.init(function(data, responseCallback) {
	alert("Got data " + JSON.stringify(data))
	if (responseCallback) {
		responseCallback("Right back atcha!")
	}
})

`bridge.send("Hi there!")`

`bridge.send({ Foo:"Bar" })`

`bridge.send(data, function responseCallback(responseData) { ... })`

Send a message to ObjC. Optionally expect a response by giving a responseCallback function.

Example:

bridge.send("Hi there!")
bridge.send("Hi there!", function(responseData) {
	alert("I got a response! "+JSON.stringify(responseData))
})

`bridge.registerHandler("handlerName", function(responseData) { ... })`

Register a handler called handlerName. The ObjC can then call this handler with [bridge callHandler:"handlerName" data:@"Foo"] and [bridge callHandler:"handlerName" data:@"Foo" responseCallback:^(id responseData) { ... }]

Example:

bridge.registerHandler("showAlert", function(data) { alert(data) })
bridge.registerHandler("getCurrentPageUrl", function(data, responseCallback) {
	responseCallback(document.location.toString())
})

iOS4 support (with JSONKit)

Note: iOS4 support has not yet been tested in v2+.

WebViewJavascriptBridge uses NSJSONSerialization by default. If you need iOS 4 support then you can use JSONKit, and add USE_JSONKIT to the preprocessor macros for your project.

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